More effective agents against solid tumors are needed, and chemically reactive compounds, which are expected to react covalently with cellular components under physiological conditions, are generally more effective against solid tumors than are antimetabolites. Our previous studies with nitrosoureas and triazenes, two classes of compounds that have furnished clinically active agents, indicate that haloethylating agents - compounds that introduce a haloethyl group into biological macromolecules - are exceptionally effective in manifesting antineoplastic activity. For these reasons, compounds that may function as haloethylating agents have been prepared and are being investigated for alkylating and cross-linking activity. Other classes of chemically reactive compounds are also included in this research. Fragmentation compounds that release a carbonium-immonium ion would, if active, comprise a new type of anticancer agent. Structures of these types will be prepared. N-Acyloxyamides and related compounds are known to react in vivo with DNA, RNA, and proteins. Several variants of this type of structure have been synthesized and are being evaluated for antileukemic activity. Certain dialdehydes have antineoplastic activity. Further investigations of this class of compounds to delineate structural requirements for activity are being carried out by preparing variously substituted 1,5-pentanedials. The objectives of the proposed work are to synthesize additional compounds representative of these types of structures, evaluate these compounds for antineoplastic activity in vivo and in vitro, and investigate the biochemical mechanism of action of active agents.